For
centuries, coffee has caused a stir over health impacts, good
or bad, with many people resigned to accept it as a guilty
pleasure.

But in a
full turnabout since the 1980s, science now extols its virtues
as a generally healthful drink and kick-start for adults, with
cautions for pregnant women and those with caffeine
sensitivity and sleeping disorders.

The U.S.
Department of Agriculture now agrees that coffee doesnít
deserve its dark history and moderate consumption "can be
incorporated into a healthy lifestyle."

The
recently released 2015 Scientific Report of the Dietary
Guidelines Advisory Committee, available online, includes 209
references to coffee, most of them favorable, particularly for
those who donít add cream and sugar and limit daily
consumption to three to five cups and no more than 400
milligrams of caffeine.

Itís
the first time the committee has addressed the health effects
of coffee and caffeine. Every five years, the USDA uses the
report to establish science-based dietary guidelines.

"Strong
and consistent evidence shows that consumption of coffee
within the moderate range Ö is not associated with increased
risk of major chronic diseases, such as cardiovascular disease
and cancer and premature death in healthy adults," the
report states in awarding coffee a "strong" grade.

"Itís
long overdue for them," according to the author of
"Uncommon Grounds: the History of Coffee and How it
Transformed our World."

"You
canít study people as you do rats," said Mark H.
Pendergrast, a Harvard-educated independent scholar.
"There have been many mistakes in confusing causality
with correlation. But, in general, it seems that coffee now is
getting a pretty clean bill of health."

As it
turns out, the bean-like seeds inside the coffee plantís red
and purple berries can reduce the risk of type 2 diabetes by
36 percent with protective effects against liver and
endometrial cancers. Slight benefits were noted for other
cancers the report didnít identify.

Overall,
research found reductions in mortality among regular coffee
drinkers. Studies not cited in the report showed benefits in
preventing depression and Alzheimerís disease, among other
neurodegenerative conditions.

The
report even says decaffeinated coffee reduces the risk of
diabetes and possibly lung cancer. While some advantages are
attributable to caffeine, the 1,000 constituent compounds in
coffee, including many healthful antioxidants known as
polyphenols, may explain the positive health outcomes.

"Strong
evidence supports a protective effect of moderate coffee
consumption on chronic disease risk in healthy adults, but its
association among those with existing diseases has been less
studied," the report states. "Given that a
substantial number of people suffer from these chronic
diseases, the role of coffee in preventing other health
outcomes in such groups remains understudied."

Coffee
with its devilish color and bitter, acidic taste has held
ground as one of the most popular beverages over the
centuries, despite concerns and bad publicity about its effect
on health. Several decades ago, it wrongly was blamed for
pancreatic cancer, breast lumps, birth defects and heart
disease.

It has
long been condemned as an addictive drug that energizes some
people and makes others jittery.

Thatís
why Pendergrast opens his book with these words:
"Throughout coffeeís history, critics have accused the
drink of causing horrendous health problems, while those who
love the brew have espoused its almost miraculous curative
powers. This extreme devotion and condemnation continues
today."

Coffeehouses
throughout Europe became popular centuries ago with the
preference, noted by a 17th-century writer, for coffee as a
more "wakeful and civil drink" instead of beer each
morning, earning coffee credit for bringing sobriety to
England. Gustav III, the king of Sweden prior to his
assassination in 1792, considered coffee a poisonous detriment
to public health. He tested this idea by requiring one
criminal twin to consume three daily pots of coffee and the
other to drink three pots of tea. Both outlived officials
monitoring the experiment and the assassinated king. The tea
drinker died first at 83.

Such
claims persisted until the 1980s, when "coffee was
associated with over 100 diseases and disorders and, though
subsequent studies threw every negative finding into question,
the implanted fears led more consumers to decaffeinated
alternatives or away from coffee completely," the
Pendergrast book states.

On its
website, the Mayo Clinic also says coffee studies failed to
differentiate between heavy coffee consumption and habits
often associated with coffee drinking, including smoking and
physical inactivity.

It says
coffee actually improves cognitive function and lowers the
risk of depression; Pendergrast adds that coffee drinkers are
less likely to commit suicide. "Thereís been a cultural
shift," he said, "and you are right to focus on it.
Itís a big deal."

But the
battle continues. The Royal Society of Chemistry, an
international group of chemical scientists based in the U.K.,
says two of the 1,000 compounds in coffee are carcinogens
whose levels depend on what coffee beans are used and how they
are roasted. The darker it is the better. But coffee has yet
to be linked with cancer.

High
consumption of unfiltered coffee (boiled or espresso) also has
been associated with mild elevations in cholesterol levels,
the Mayo Clinic states. Other studies found that two or more
cups of coffee a day can increase the risk of heart disease in
people with a specific ó and fairly common ó genetic
mutation that slows the breakdown of caffeine in the body.
"So, how quickly you metabolize coffee may affect your
health risk," the clinic says.

The
committee report also says "individuals who do not
consume caffeinated coffee should not start to consume it for
health benefits alone." Pendergrast says the government
is reluctant to recommend anything thatís addictive.

But the
chief concern isnít the coffee but such additives as cream,
milk and sugars. "Care should be taken to minimize these
caloric additions," the report says.

And
while the artificial sweetener aspartame is considered safe,
the report notes some uncertainty "about increased risk
of hematopoietic (blood) cancer in men, indicating, again, a
need for more research."

Pendergrastís
book says humans tend to demonize or glorify things upon which
they depend. For that reason, he expects arguments between
those who consider coffee to be a "black, thick, nasty,
bitter, stinking, nauseous puddle water" (as a petition
of 17-century English women complained) and those who regard
it as a "beverage of the friends of God" (to quote a
16th-century Arabic poet) to continue into the indefinite
future.